Electronic devices are found in all aspects of life. Of particular import are computers, which are found in homes and offices throughout the world. It is now routine to ship computers and computer components long distances, be it factory to retail outlet, factory to consumer, or warehouse to consumer.
One problem that continues to plague computer components is damage from physical shock. Physical shock can occur in many ways. During handling in a factory, retail store, or in a shipping warehouse, a component might be dropped. During transportation, the vehicle carrying the electronic device might encounter potholes and other obstacles which jar the vehicle, translating vibration and shock to the electronic device.
The problems caused by physical shock are even more pronounced in computer components having movable parts. For instance, hard disk drives have many moveable parts. A drop of four inches results in a shock of ˜300 G (300 times the force of gravity) to a hard disk drive. Such a shock causes particular damage to the bearing races of the hard disk drive.
Typical disk drives use ball bearings in the races of a spindle supporting the disks as well as the drive motor. FIG. 1 illustrates a detailed view of ball bearings 100 and races 102, 104. The bearings 100 rest against inner and outer races 102, 104. Because the bearings 100 are spherical, they only have one point of contact on each race 102, 104. The bearings 100 are much harder than the races 102, 104. When a disk drive is idle and is jarred, the ball bearing mechanism is more susceptible to damage by a shock and even physical movement. Because the motor is not spinning, the ball bearings 100 are pressed against a race, resulting in lubricant depletion at the point of contact of the ball bearing 100 and the race. Over time, even slight movement of the ball bearing 100 will cause pitting and gauling on the race. When the drive is finally put into use, the pitting and gauling cause an audible click each time a bearing encounters one of these damaged portions. When the drive is activated, the clicking turns into a high frequency audible noise or “whine” that is undesirable.
Another type of bearing is a fluid dynamic bearing (FDB). FIG. 2 illustrates an FDB 200. An FDB is essentially a cylinder 202 inside another cylinder 204, the first cylinder 202 being surrounded by a fluid. At high speeds, the inner cylinder 202 is centered in the outer cylinder 204. However, in a stop condition, the inner cylinder 202 will tend to pivot such that the cylinders 202, 204 contact each other. A physical shock will cause more damage to FDBs than an equivalent shock would cause to a ball bearing structure as the ball bearings tend to distribute the load. In an FDB 200, there is only one point of contact to absorb the energy of the shock. Thus, the damage to the outer cylinder 204 will be more profound. Any scarring of the outer cylinder 204 will cause mechanical interference of the journal bearing. The interference will cause scratching which will ultimately collect debris and will ultimately alter the properties of the fluid, creating instability, i.e., vibration, of the FDB 200.
What is therefore needed is a new device that reduces rotation of the motor and disk(s) of a hard drive to prevent damage to the bearing races caused by rotation of the motor and disk(s) during physical shock.